Microsoft SharePoint Remote Code Execution Vulnerability

Source data

Overview

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

Impact & technical details

Remote Code Execution

I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running? Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability.

How could an attacker exploit the vulnerability? In a network-based attack, an attacker authenticated as at least a Site Owner, could write arbitrary code to inject and execute code remotely on the SharePoint Server.

According to the CVSS metric, the attack vector is network (AV:N) and the attack complexity is low (AC:L). What does that mean for this vulnerability? The attack vector is Network (AV:N) because this vulnerability is remotely exploitable and can be exploited from the internet. The attack complexity is Low (AC:L) because an attacker does not require significant prior knowledge of the system and can achieve repeatable success with the payload against the vulnerable component.

CVSS base score

9.8 / 10

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Highest base score supplied by MSRC for this record; the vector belongs to that score. Ratings can vary by product. Microsoft Important is displayed as High; Moderate is displayed as Medium.

Affected products

• Microsoft SharePoint Enterprise Server 2016
• Microsoft SharePoint Server 2019
• Microsoft SharePoint Server Subscription Edition

Source guidance

Remediation

• Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

At least one Microsoft vendor-fix reference is available. Check each affected product for its applicable update, prerequisites, and supported version.

Authoritative sources & updates

Findings and update information come from the linked publishers. GTP compiles the public record and provides the recommendation above. CVSS ratings shown here come from Microsoft. NVD references provide additional public context.

• Microsoft Security Response Center (opens in a new tab)
• Microsoft security update · 5002891 (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• Microsoft security update · 5002883 (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• Microsoft security update · 5002882 (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• CISA Known Exploited Vulnerabilities (opens in a new tab)
• Authoritative advisory (opens in a new tab)
• Authoritative advisory (opens in a new tab)
• NIST National Vulnerability Database (opens in a new tab)